Dragonfly Nymphs in Tilapia Ponds – Friend or Foe?

If you’ve spent time looking closely at your tilapia ponds, you may have noticed strange, bug-like creatures clinging to the walls or darting through the water. At first glance, they might look like oversized mosquito larvae – but in reality, these are dragonfly nymphs, the underwater stage of dragonflies.

What Are Dragonfly Nymphs?

• Dragonflies spend most of their lives underwater as nymphs before transforming into the familiar flying adults we see around ponds and dams. These nymphs can grow up to an 25 mm  (sometimes even larger) and are equipped with extendable jaws that they use to ambush prey.
• They’re patient hunters, often hiding against pond walls or in vegetation before lunging forward to snatch anything small enough to eat.

Are They Dangerous for Tilapia?

For adult and juvenile tilapia: Dragonfly nymphs are harmless. Tilapia that are big enough will easily avoid them. Some fish may even eat the nymphs if they get the chance.

For fry and fingerlings: This is where the problem lies. Dragonfly nymphs are effective predators and won’t hesitate to feed on tilapia fry. If you’re raising fingerlings for grow-out, the presence of dragonfly nymphs in your pond could reduce survival rates.

Benefits of Dragonfly Nymphs

Before writing them off as pests, it’s worth noting their benefits too:

• Natural mosquito control: Dragonfly nymphs are excellent at keeping mosquito larvae under control. This means fewer mosquitoes around your farm or backyard.
• Part of a balanced ecosystem: They’re an important food source for larger fish, birds, and amphibians.

How to Manage Them in Tilapia Ponds

If you’re growing larger tilapia, dragonfly nymphs don’t pose a serious threat. But if you’re hatching or nursing fry, here are a few steps to protect your stock:

1. Manual removal: Net out visible nymphs during pond checks.
2. Nursery nets or tanks: Keep fry in fine-mesh enclosures or separate nursery tanks to protect them.
3. Cover fry tanks: Prevent adult dragonflies from laying eggs by using netting or covers over nursery tanks.
4. Control vegetation around fry ponds: Dragonflies prefer to lay eggs in areas with aquatic plants. Reducing these helps lower egg-laying opportunities.

Conclusion

Dragonfly nymphs are both friends and foes in tilapia farming. They’re fantastic at keeping mosquitoes in check and are part of a healthy aquatic environment, but they can become a problem if you’re raising fry.

At Zeekoevalley Aquatics, we recommend keeping an eye out for these predators, managing them in fry ponds, and embracing their benefits in grow-out ponds. With a balanced approach, you can enjoy healthier ponds and higher tilapia survival rates.